An FBI whistle-blower contends that the bureau's headquarters removed important information from a search warrant application whose rejection kept the government from learning more about
terrorism suspect Zacarias Moussaoui before Sept. 11.

Coleen Rowley wrote in a memo earlier this week that agents in Minneapolis became so frustrated by roadblocks erected by supervisors in Washington they began to joke that FBI headquarters was
becoming an "unwitting accomplice" to Osama bin Laden (news - web sites)'s efforts to attack the United States, said government officials who have seen the memo.

As new details emerged about the letter Rowley wrote to FBI Director Robert Mueller, key members of Congress sought on Friday to extend her whistle-blower protections and invited more agents
to come forward.

"We encourage more of the same," said House Intelligence Committee Chairman Porter Goss, R-Fla.

A joint panel of House and Senate members, meanwhile, set the first hearings in June to examine what the government knew before Sept. 11 about terrorist threats and what mistakes it made.

Officials familiar with Rowley's memo, speaking on condition of anonymity, said she alleged FBI headquarters terrorism supervisors rewrote the Minnesota office's warrant applications and
affidavit and removed intelligence about Moussaoui before sending them to a legal office that then rejected them as insufficient.

She alleged that some of the revisions "downplayed" the significance of some intelligence linking Moussaoui to Islamic extremists, and blamed the changes on a flawed communication
process.

"Obviously, verbal presentations are far more susceptible to mischaracterization or error," Rowley, an FBI counsel, wrote in her 13-page letter, excerpts of which were obtained by
The Associated Press.

The Minneapolis office was concerned after arresting Moussaoui at a Minnesota flight school in August 2001 that he was seeking to hurt Americans and wanted to gather more information through
national security and search warrants, including getting information off his computer.

Some of that information came from an associate of Moussaoui who told the FBI the flight student held extreme anti-American views. Other intelligence came from France linking Moussaoui to
radical Islamic extremists in the region, although not directly to al-Qaida, officials said.

The officials said Rowley identified the warrant revision process as flawed, particularly complaining that Minnesota was never consulted about the changes that were made before the warrant
applications were forwarded to the offices that rejected them.

Officials said Rowley in other parts of the memo attacked the public explanations that Mueller and other FBI senior officials have offered about why the FBI failed to connect the dots before
Sept. 11.

Rowley wrote she had come to the "sad realization" that officials had skewed facts in the post-Sept. 11 accounts and were trying to "circle the wagons" to protect FBI
headquarters from embarrassing disclosures.

She also criticized the culture of Washington headquarters, saying FBI higher-ups were too concerned with "petty politics" and too afraid to make tough decisions that could affect
their career ascensions, the officials said.

Several times, Rowley complained in the letter that Minneapolis had never been told of a separate memo written in July by a Phoenix FBI agent warning that Arab pilots in Arizona with ties to
radical Muslims were training at flight schools.

"Headquarters personnel never disclosed to the Minneapolis agents that the Phoenix Division had only three weeks earlier warned of al Qaeda operatives in flight schools seeking flight
training for terrorist purposes," Rowley wrote.

Actually, the Phoenix agent had not connected the pilots to Osama bin Laden but rather to a militant Islamic group in London whose leader received communications from bin Laden encouraging
violence.

FBI officials have repeatedly said the agency failed to connect the two matters before Sept. 11.

But on Friday, Senate Judiciary Committee Chairman Patrick Leahy, D-Vt., and committee members Arlen Specter, R-Pa., and Charles Grassley, R-Iowa, questioned whether the head of the FBI's
radical fundamentalist anti-terrorism unit in Washington may have handled both matters and been in a position to make the connection.

Officials said the unit chief was directly involved in the Moussaoui deliberations in August and was one of the first names copied on the Phoenix memo a month earlier.

But one law enforcement official who demanded anonymity said the unit chief contends he never saw or was aware of the Phoenix memo being handled by his unit before Sept. 11 even though he was
copied in on it.

"Please explain his role ... (and) what connection, if any, he or others drew between the two ongoing investigations; and whether he or others brought such a connection to the attention
of higher-level FBI officials," the senators wrote.

Separately, Grassley disclosed he has given Rowley "written assurance that she will be protected for her cooperation with the Judiciary Committee's investigation" and urged Mueller
"to ensure there is no retaliation against Ms. Rowley."